Understanding Print Sizes and Aspect Ratios

Most people are at comfortable with the process of purchasing photographic prints. There are many alternative printing companies online and in the high street, most with a plethora of easy-to-use options.

If there is confusion, it lies in the difference between print sizes and aspect ratios.  Print sizes tend to better understood, because it is easier to visualise overall print area: the comparative print sizes below highlight that the 10×8” print (80 square inches) is more than the double the area of the 7×5” print (35 square inches).   So it fairly intuitive to assess whether a particular print size will work well above the TV; or whether people’s expressions in a large group photo will be clearly detailed enough.

Graphic explaining different print sizes.

So what about aspect ratios? In its simplest form, a print aspect ratio is simply a measurement of its width compared to its height, in the form of a ratio.    So for example, a full frame image taken from a SLR camera, without any cropping, is in the ratio 3:2. Or expressed another way, the width of the image is 1.5 times the height of the image.

How does aspect ratios relate to cropping?  The image below is a full frame 3:2 image.  If we printed this as a 6×4” print, it would look perfect – just the same as we see it below. But what if we wanted this image in another common print format – a 10×8”?  This would unfortunately cut the hand off – or at least an important part of the compositon.  The reason is that, although the 10×8” print is significantly larger than a 6×4”, its aspect ratio is 5:4.  In another words this, the larger 10×8” print’s aspect ratio is squarer (sometimes described as fatter).

Baby photo to show effect of cropping with different aspect rations

What about the two other common small print formats – the 7×5” and 8×6”?  They are more elongated than the 10×8” but squarer than the 6×4”.  If you remember about fractions and ratios from school, these two prints sizes have image ratios of 5.6:4 and 5.3:4, which clearly lie between 6:4 and 5:4.  If this seems more confusing, it’s probably to think in terms of the width as a multiple of the height (or just refer to this table below!).

What does this mean for in practice for printing your favourite images? Clearly not every image will work for all print sizes.  So some care needs to be taken when deciding on print size. Many online printing labs will let customers crop and preview the print before ordering.  So take the time to use this facility.  Sometimes, this may actually allow and encourage you to be bolder and more creative with your cropping.  For example, a squarer crop of the full image might cut off a limb in a portrait, and make the composition look awkward. But using a tighter cropped version of the same aspect ratio that frames just the head and shoulders of an image (and cuts out all of the limbs altogether) might look equally as striking.

Baby photo highlighting the merit of a tight crop for a square print

At Light Republic, because customers often purchase high-resolution images, we often aim to shoot in a “wide” (or “zoomed out” fashion), which allows flexibility when choosing between different standard print sizes. For example, this particular image would work fairly well in 7×5”, 8×6” and 10×8” formats.

Family photo highlighting how different crops will work well

However, taking the idea of printing flexibility too far can potentially detract from good and interesting compositions.  The image below has a strong 2:1 panoramic (sometimes called “letterbox”) composition. 

Family portrait in panoramic format.

What can we do with this if we wanted a 10” print, for example?  We could distort the image into a 10×8” print ratio (Image A below).  Not a good look!   Or we could  add a lot of white space to achieve a 10:8 aspect ratio (Image B).  Again, not a good.

Two variants of a family image inappropriately forced into a square format.

So this need to be printed in a 2:1 ratio such as 10×5” or 20×10”.  In terms of presentation, if you were asking Light Republic (or any professional framing company) to make a wall display product, there wouldn’t be a problem. A bespoke frame is constructed around the print.

Family portrait with a bespoke frame

If you have purchased a 10×5” print yourself, the pertinent issue is that it is very difficult to buy a budget off-the-shelf frame for this size. A work-around is to buy a bespoke mount.  In this case, you might specify the mount to contain a 10×5” aperture with overall dimensions of 14×11” (a frame size that is relatively easy to purchase in the high street).   Frame Lizard, for example, allows you to easily specify bespoke sizes and colours online.